United States
Environmental Protection
Agency
Hazardous Waste Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S8-87/056 Jan.1988
Project Summary
Manual of Procedures and
Criteria for Inspecting the
Installation of Flexible
Membrane Liners in Hazardous
Waste Facilities
Thomas D. Wright, William M. Held, J. Rodney Marsh, and Louis R. Hovater
Under the Hazardous and Solid
Waste Amendments (HSWA) of 1984,
certain landfills and surface impound-
ments are required to assure proper
containment of wastes by the use of
liner systems. Proper installation
procedures for the flexible membrane
liner (FML) system must be followed
to ensure containment of wastes. This
manual is intended to assist an inspec-
tor in performing all aspects of a proper
FML installation inspection.
Four types of FMLs are addressed in
this manual: PVC, CSPE, CPE, and
HOPE. The manual covers seven instal-
lation operations. These operations
include unloading and storage of FML,
preparation and maintenance of sup-
porting surface (both earth and other
supporting surfaces), placement of
FML on the supporting surface, seam-
ing operations, anchoring and sealing
(anchoring in earth and to concrete,
piping, etc.), testing (both the seams
and the integrity of the entire FML
installation), and covering the FML
(earth, concrete, geotextiles, or drain-
age nets).
The manual describes each operation
and sub-operation, and gives recom-
mended inspection procedures, inspec-
tion frequencies, and interpretations.
The types of documentation necessary
for each inspection are also discussed.
Where appropriate, alternatives to
recommended inspection procedures
ar» provided. Inspection checklists are
included for each operation to aid the
inspector in the field.
This Project Summary was devel-
oped by EPA's Hazardous Waste Engi-
neering Research Laboratory. Cincin-
nati, OH , to announce key findings of
the research project that is fully doc-
umented in a separate report of the
same title (see Project Report ordering
information at back}.
Introduction
One of the major problems associated
with hazardous waste landfills and
surface impoundments has been hazard-
ous leachate and associated ground-
water contamination. Controlling leach-
ate with flexible membrane liners (FMLs)
is a function of proper liner selection,
good design, and proper installation. Poor
performance in any one of these three
areas can cause an FML system to fail.
In terms of FML installation, defective
field seaming, improper subgrade prep-
aration, and bad seals around penetra-
tions into the liner (such as drainage
pipes) can be considered to be the most
frequent causes, but there are several
other factors which must also be con-
sidered. Poor weather conditions during
installation, steep side slopes, vegetation
growing through the liner, worker inex-
perience, insufficient anchoring, lack of
protective cover, etc., may all contribute
to liner failure. However, until this
manual there were no set guidelines
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which FML installers could follow for
testing and inspecting these areas.
This manual is intended for use by
engineering firms, dischargers of wastes
to land, operators, and regulatory offi-
cials. The manual is intended to provide
criteria and procedures for inspecting
and testing FML installations in land-
based waste containment facilities.
Throughoutthe inspection process, the
inspector will work with representatives
of the various participants including the
general contractor, the subcontractor^
and the design engineer. It is the
responsibility of the inspector to ensure
that installation design plans and spec-
ifications are followed. The inspector has
the authority to reject the work until
noncomplying items (e.g., improper
seaming) are corrected or until field
conditions (e.g., ambient temperature is
too low/high) warrant resumption. It is
essential that the inspector maintain a
cooperative attitude toward FML
installers while assuring proper FML
installation.
Procedures
The information in this manual was
derived from two principal sources—the
published literature and interviews. An
extensive literature review was con-
ducted to identify various FML installa-
tion procedures in use or recommended
by liner suppliers and installers. The
bibliography of the manual contains over
130 references.
Secondly, a number of researchers and
liner industry personnel who are involved
in FML installation were contacted and
interviewed. The combined literature
search and interview process resulted in:
• An understanding of why inspections
are important.
• Identification of areas needing
inspection.
• Identification of tests, test frequency,
and sample size.
• Identification of acceptance criteria.
Manual Contents
The manual is limited to discussion of
the four FMLs most commonly used for
waste containment:
• Polyvinyl chloride (PVC)
• High-density polyethylene (HOPE)
• Chlorosulfonated polyethylene (CSPE)
2
• Chlorinated polyethylene (CPE)
The manual is organized in seven chap-
ters that sequentially cover each FML
installation procedure, as follows:
• On-site unloading/storage of FML.
• Preparation and maintenance of the
FML supporting surface.
• Placement of FML on supporting
surface.
• FML seaming operations.
• FML anchors/attachments.
• FML testing, including seam testing
and testing of the integrity of the
entire FML installation.
• FML cover operations.
On-Site Unloading/Storage
The initial step of FML inspection is
to make sure the specified FML type and
accessories are delivered to the job site
undamaged. This is primarily the respon-
siblity of the installation supervisor.
However, the inspector should also make
spot checks.
Once the FML is accepted as undam-
aged, it is important it be carefully
unloaded onto a surface that is relatively
level and smooth, free of rocks, holes and
debris to prevent damage to the FML.
FML materials and accessories are
best kept out of direct weather conditions
to prevent possible damage from sun,
wind, or moisture. Often the storage area
is in the same location as the unloading
area. If this is the case, the area must
be large enough so that unloading,
storage, and transport can operate
smoothly. If the storage area is in a
building, proper accessibility and
maneuverability are of great value. If the
storage area is open it should generally
be fenced for security.
Specific sections and subsections in
the manual that address inspection
criteria and procedures for on-site
unloading/storage are listed below.
• Material check:
—FML.
—Accessories.
• Unloading and handling equipment.
• Unloading area:
—Accessibility.
—Type.
—Location.
—Unloading and handling.
• Storage area: *
—Type.
—Location.
—Climatic conditions.
—Other factors.
Preparation and Maintenance
of Supporting Surface
For purposes of the manual, a support-
ing surface is defined as the surface on
which the FML will be placed. For a single
FML system, the supporting surface will
probably consist of compacted earth,
concrete, asphalt, or other material. If a
second FML is specified (a double FML
system), the supporting surface for the
top FML will generally consist of a
drainage net, a granular soil layer, and/
or a geotextile fabric.
Whether a single or double FML
system, it is assumed that the supporting
surface has been brought to final grade,
and that the soil subgrade (if applicable)
has been compacted and is structurally
sound.
If the supporting surface is soil, the
inspector should be aware that the soil
type will effect the installation procedure.
For example, clayey soils form surface
cracks when dried, and sandy soils form
depressions under foot and vehicular
traffic. A table containing soil character-
istics pertinent to FML installations is
included in the manual.
A soil supporting surface should be
free of all vegetative growth prior to final
preparation. Burrowing animals (e.g.,
gophers and ground squirrels) should
also be removed and/or their tunnels
destroyed. Final preparation consists of
removing all clods, pebbles, etc., filling
voids, and rolling/compacting the
surface.
After the supporting surface has been
accepted for FML placement, it is impor-
tantto maintain its integrity by mitigating
or correcting damage caused by wind or
storm water erosion, and saturation or
ponding by storm water.
Supporting surfaces other than soil
(e.g., concrete and asphalt) must also be
inspected to assure that they are smooth,
free of surface voids or depressions, and
that there are no abrupt changes in
abutting surface elevations.
The specific sections and subsections
as they appear in the manual are as
follows:
• Soil supporting surfaces:
—Type of soil.
—Vegetation removal.
—Burrowing animals, ants, and other
pests.
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—Preparation of finished earth sup-
porting surface
—Maintenance of earth supporting
surface.
• Other supporting surfaces-
—Concrete.
—Asphaltic supporting surfaces.
—Geotextile fabric.
—Drainage layers.
Placement of FML on Support-
ing Surface
Placement of FML on the supporting
surface includes: transporting the FML
to the working area; removing the FML
from its packaging; and spreading the
FML sheets in their appropriate loca-
tions, making sure each FML is not
damaged (e.g., has no holes, etc.) and
is ready for seaming.
Prior to commencing placement of the
FML, the inspector should first ensure
that placement equipment is on site and
in working order; a sufficient number of
qualified placement personnel are on
site, and weather conditions are suitable.
Specific sections and subsections in
the manual discussing placement
inspection criteria and procedures are
listed below.
• Placement equipment.
• Personnel
• Weather conditions.
• FML layout:
—Type of FML
—Thickness of FML.
—Accessibility.
—Placement on slopes.
—Placement around penetrations.
Seaming Operations
FML seams can be prepared either in
the factory or in the field. Factory seams
are manufactured in a controlled envir-
onment, and seam quality is generally
superior to field seams. Since the field
inspector is not responsible for observing
the making of factory seams, only a brief
summary of factory seaming techniques
is provided in the manual as background.
However, the overall quality assurance/
quality control program should require
factory inspections.
The primary thrust of the manual is
to discuss field seaming operations and
the inspection thereof However, the
discussion is necessarily general
because each FML manufacturer/fabri-
cator has specific (and often proprietary)
seaming equipment and seaming
procedures.
Prior to the start of FML seaming
operations, the manufacturer should
provide the inspector with precise spec-
ifications on the equipment and proce-
dures that will be used to seam their
material in the factory and field. In
addition, the inspector should meet with
the manufacturer's/fabricator's repre-
sentative for an explanation and demon-
stration of the seaming equipment and
procedures to be used on the job.
Seaming methods described include
liquid applied solvent or adhesive
methods; thermal methods; vulcanizing
tapes and adhesives; and tape and
mechanical seaming methods.
Specific sections and subsections in
manual discussing seaming inspection
criteria and procedures are listed below.
• Seaming methods
—Factory seams.
—Field seams.
• Equipment.
• Personnel.
• Environmental conditions.
• Seaming.
Liner Anchors/Attachments
One of the most common areas of
failure in an FML installation is the
attachment of the FML to another
surface. In general, these attachments
consist of perimeter anchors or attach-
ments to structures, such as pipes or
columns, within the facility.
The manual provides the inspector
with guidance on specific types of
anchors/attachments, and also deli-
neates several general practices and
procedures that should be followed.
These include ensuring that placement
equipment is on site, in working order,
and that a sufficient number of qualified
placement personnel are on site
Specific sections and subsections in
the manual discussing liner anchors/
attachments inspection criteria and
procedures are listed below.
• Placement equipment.
• Personnel
• Anchors/attachments.
—Earth anchor trenches.
—Inspection procedures.
—Concrete and piping.
—Concrete.
—Battens and bolts.
—Reglets.
—Piping.
FML Testing
This chapter of the manual introduces
the inspector to methods that are used
to test factory and field seams and
patches. These test methods can be
destructive and/or nondestructive. Non-
destructive tests are performed in the
field on in-place FML. Testing is per-
formed by the contractor and should be
observed by the inspector. This type of
test retains the integrity of the FML seam
or sheet being tested. Destructive tests
are performed m either the field or
laboratory. The intent is to determine the
strength characteristics of a seam sam-
ple by stressing the sample until either
the seam or the FML sheeting fails. Only
tests performed in the field should be
observed by the inspector; however, the
inspector should review laboratory test
results to ensure acceptable results were
obtained.
Destructive tests can be performed on
samples taken from either in-place FML
seams, sheets, and patches (destructive
sampling), or on samples of representa-
tive FML seams and patches fabricated
by the seaming/patching crew from the
same material, and using the same
seaming methods as those being used
to make the in-place seams and patches
(nondestructive sampling). The inspector
should verify that the type of samples
used are those specified in the quality
assurance/quality control plan.
Field test methods described in the
manual are probe, air lance, vacuum box,
ultrasonic pulse echo, ultrasonic impe-
dance plane, spark, pressurized dual
seam, electrical resistivity, hydrostatic,
seam strength peel, and seam strength
shear tests. Laboratory test methods
described are the bonded seam strength
shear and bonded seam strength peel
tests.
Specific sections and subsections in
the manual discussing FML testing
inspection criteria and procedures are
listed below.
• Field tests:
—Air lance.
—Probe.
—Vacuum box.
—Ultrasonic pulse echo.
—Ultrasonic impedance plane.
—Spark testing.
—Pressurized dual seam.
—Electrical resistivity.
—Hydrostatic.
—Seam strength, peel.
—Seam strength, shear.
• Laboratory tests:
—Bonded seam strength, shear.
—Bonded seam strength, peel.
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storage at the site through actual place'
ment and final cover.
Use of the manual described herein
should lead to standardization of inspec-
tion procedures and insurance that FMLs
at hazardous waste sites are properly
installed.
FML Covers
The primary function of the inspector
is to ensure that the FML is not damaged
during cover placement operations.
Covers over an FML will generally consist
of earth (clay [natural and/or bentonite
added], sand, silt, gravel, or a combina-
tion of soils) or some other material such
flS Portland cement/gunite, geotextile or
drainage net.
The majority of the above covers are
placed over an FML as a protective layer
against mechanical, weather or other
potential damage Drainage nets and
sand and gravel are used as a permeable
layer to convey leakage and/or leachate
that may accumulate on the upper and/
or lower FML after put into use.
Specific sections and subsections in
the manual discussing cover type and
placement inspection criteria and proce-
dures are as follows:
• Soil covers:
—Equipment.
—Personnel.
—Weather conditions.
—Earth cover placement.
• Portland cement concrete/gunite:
—Equipment.
—Personnel.
—Weather conditions.
• Drainage nets and geotextiles.
Conclusions
An improperly installed FML is little
better than no liner at all, and may
actually be worse, because it provides a
false sense of security. Consequently,
the role of the inspector in ensuring
proper FML installation can be critical.
The inspector needs to be aware of all
procedures and criteria essential for
proper installation, from unloading and
Thomas D. Wright (formerly with SCS Engineers); William M. Held is with SCS
Engineers. Covington, KY 41017; J. Rodney Marsh is with SCS Engineers,
Long Beach, CA 90807; and Louis R. Hovater is with Hovater Engineers,
Laguna Hills, CA 92623.
Charles Moench, Jr., is the EPA Project Officer (see below).
The complete report, entitled "Manual of Procedures and Criteria for Inspecting
the Installation of Flexible Membrane Liners in Hazardous Waste Facilities,"
(Order No. PB 88-131 313/AS; Cost: $19.95) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. I/'A 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Hazardous Waste Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
U.S. OFFICiAL MA
£250(09 I
Official Business
Penalty for Private Use S300
EPA/600/S8-87/056
0000329 PS
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